ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2021
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IF 9.028
Haiyang Tang,Hongli Zhong,Yang Pan,Qing Zhou,Zongli Huo,Wenhai Chu,Bin Xu
pH adjustment prior to extraction is an important step in water sample pretreatment processes for exploration of new/unknown disinfection byproducts (DBPs) in drinking water. To achieve a better extraction efficiency, the pH of a water sample is usually adjusted to a low level (e.g., < 0.5) to ensure that target DBPs are in their neutral forms. However, such a practice may elude some amphoteric DBPs (especially those nitrogenous DBPs with multiple functional groups), which can accept protons at a low pH and lose protons at a high pH. In this study, with careful extraction pH selection and optimization, we first report the detection and identification of a new group of heterocyclic nitrogenous DBPs, halogenated pyridinols, in simulated drinking water using ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry and time-of-flight mass spectrometry, including 5-chloro-3-pyridinol, 2-bromo-3-pyridinol, 2,6-dichloro-4-pyridinol, 2,6-dibromo-3-pyridinol, 3-bromo-2-chloro-5-pyridinol, 5-bromo-2-chloro-3-pyridinol, 3,5,6-trichloro-2-pyridinol, and 2,4,6-tribromo-3-pyridinol. On the basis of the speciation of dissociated chemical species and recovery tests at different extraction pH values, it was found that, only at a pH of 3.0, all the eight new DBPs could achieve recoveries of >50%. With subsequent instrumental parameter optimization, the method detection and quantitation limits of the eight new DBPs were determined to be 0.04–1.58 and 0.15–4.11 ng/L, respectively. The optimized method enabled an accurate detection of the eight new DBPs in two real drinking water samples. Further aided with in vivo developmental and acute toxicity assays using zebrafish embryos, the developmental and acute toxicity of the new DBPs were found to be slightly lower than those of halogenated benzoquinones but dozens of times higher than those of commonly known DBPs such as tribromomethane and iodoacetic acid.
研究领域:
环境科学
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分析化学
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毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
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2022
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IF 6.056
Qianwen Zheng,Rui-Bo Jia,Donghui Luo,Lianzhu Lin,Chong Chen,Mouming Zhao
In this study, five Fucus vesiculosus polysaccharides (FVPs; FVP-2, FVP-4, FVP-7, FVP-10, and FVP-13) were extracted by different pH, and their physicochemical characteristics and α -glucosidase inhibitory activity were investigated. Results showed that extraction pH significantly affected the chemical composition, molecular weight, zeta potential, structure characterization, and rheological property of FVPs. The viscosity consistency index of Fucus vesiculosus polysaccharides at high concentration (40 mg/mL) were ranked in decreasing order as FVP-10 > FVP-4 > FVP-7 > FVP-2 > FVP-13, which was strictly in accordance with the order of Mw. Among the five polysaccharides, FVP-13 showed the strongest α -glucosidase inhibitory activity, which might be related to its the lowest Mw and relatively higher xylose content. Fluorescence quenching analysis indicated that the interaction of FVPs and α -glucosidase was predominated by a dynamic mechanism. Thermodynamic analysis showed that the main driving forces for the interaction was hydrophobic interaction. Circular dichroism spectrum analysis found that FVPs could induce the secondary structure of α -glucosidase changes like the decrease of β -sheet content and the increase of β -turn and random coil content to inhibit α -glucosidase activity. These results suggested that extraction with high pH was an efficient method to obtain FVPs with strong α -glucosidase inhibition activity.
研究领域:
海洋生物学
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食品科学
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药理学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CEREAL SCIENCE
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2021
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IF 3.616
Lanlan Wu,Jianhua Li,Weijing Wu,Libo Wang,Fei Qin,Wen Xie
The tartary buckwheat protein isolates (TBPIs) were extracted by different pH combined with isoelectric precipitation. The impacts of extraction pH on Osborne-type protein fractions, functional properties, structural properties, and in vitro gastrointestinal digestion were investigated. The result showed that alkaline extraction was effective to increase yield of TBPI. With increase of extraction pH, the content of albumin in TBPI gradually decreased, while content of glutenin was increased. The solubility of TBPIs extracted by pH above 12 were significantly decreased while emulsion stability was significantly increased, which was related to significant increase of surface hydrophobicity. The digestive rate of TBPIs of pH 7 and 8 were high. With increase of pH from 8 to 10, digestive rate of TBPIs decreased. It was related to the compact structure of TBPIs, which had higher α-helix content, higher disulfide bonds , and lower intrinsic fluorescence intensity. Continuous increase of pH increased digestive rate of TBPIs. It was associated with unfolded and denatured structure of TBPIs (pH ≥ 12), as evidenced by breakdown of disulfide bonds, lower α-helix structure, red-shift in intrinsic fluorescence, and dissociation of subunits. Overall, extraction pH during protein extraction has great impacts on TPBIs.
研究领域:
食品科学
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蛋白质化学
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营养学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）